It is hard to imagine any people, collectively, being better prepared for earthquakes than the Japanese. Their country is one long seismic zone, which at any moment could, literally, rock and roll. Every Sept. 1, across the archipelago, Japanese engage in exercises devoted to disaster awareness: what to do should the worst happen. The occasion resonates with history. On that date in 1923, the Great Kanto earthquake devastated Tokyo and nearby Yokohama, unleashing fire and fury that left more than 100,000 people dead. After that, Japan resolved that it would prepare for whatever cataclysm nature might throw at it.

And yet.

When a huge earthquake struck Kobe in southern Japan in January 1995, killing more than 6,400, the national government and local officials stood accused of foot-dragging — a slow response that, among other failings, cost some people their lives and left as many as 300,000 others out in the cold, homeless for far too long. Comparable indictments of the authorities were heard in 2011 after the Tohoku earthquake and tsunami, which overwhelmed parts of northeastern Japan and created the enduring nuclear nightmare at the crippled Fukushima Daiichi power plant.

Readiness, or lack of it, is also on the national mind in this country after back-to-back earthquakes rocked Southern California in late March. Damage was relatively slight. But a question that had loomed for decades suddenly gained new urgency: How prepared are Americans, especially Californians, for the anticipated killer quake routinely referred to with a mixture of dread and awe as the Big One? That question is the focus of the latest installment of Retro Report, a series of video documentaries that hark back to major news stories from the past, and examine what has happened since.

The starting point for this week’s offering is the Loma Prieta earthquake that jolted the San Francisco Bay Area on Oct. 17, 1989. Named for a mountain peak south of the bay that was near the epicenter, the 6.9-magnitude temblor killed 63 people, 42 of them when the upper level of a double-deck portion of freeway in Oakland collapsed and crushed cars below.

To some, this became known as the World Series earthquake. It struck at 5:04 p.m. as cross-bay baseball rivals, the San Francisco Giants and the Oakland Athletics, were about to start the third game of the Series in San Francisco. Some experts credit the Series with having saved lives. Normally at that hour, many more drivers would have been on the road. Instead, people were already at home or still at work gathered around televisions. (In case you care, that third game was finally played 10 days later and was won by the A’s, who went on to sweep the Giants in four games.)

After Loma Prieta and then a quake of 6.7 magnitude in 1994, California bumped up its readiness by many notches. Billions have been spent fortifying infrastructure elements like bridges, rail systems, water mains, schools and other public buildings.

In addition to the late-March temblors in Southern California, an 8.2-magnitude earthquake off the coast of Chile on April 1 focused minds anew on the work that needs to be done. A natural concern is that being better prepared is hardly synonymous with being fully prepared; if nothing else, hundreds of thousands of single-family homes across California are still vulnerable. Once memories of an earthquake fade, there is a tendency to slip back into complacency, Mayor Eric Garcetti of Los Angeles has said. This is a theme as well for Dennis Mileti, a professor emeritus of sociology with the University of Colorado, Boulder, who now lives in California and told Retro Report that humans are “wired to ignore high-consequence, low-probability events.”

Understandably, California draws the most attention, but fault lines snake through pretty much all regions of the United States except the northern Midwest. (New Yorkers tend to forget that a major fault runs along 125th Street in Manhattan. The Harlem Shake may yet refer to more than a dance craze.) Oregon in particular drew Retro Report’s interest because seismologists believe it is due, maybe even overdue, for an enormous quake that could conceivably register as much as a devastating magnitude 9.

There, the worry is the Cascadia subduction zone, a fault system that runs from Vancouver to Northern California, roughly 100 miles offshore. In a worst-case scenario, experts say, that earthquake could be many hundreds of times more powerful than Loma Prieta.

The Fukushima Daiichi meltdown, too, has put a spotlight on the soundness of nuclear reactors in this country. Some plants, including Indian Point 2 north of New York City, face the prospect of expensive safety reviews to ensure that they can withstand the most severe quake that could strike them.

Preparing for the worst is, obviously, basic prudence. But perhaps a certain fatalism is an inescapable component of any readiness blueprint, captured neatly in an old Yiddish saying: Man plans, and God laughs. One does not hear Yiddish all too often in Japan, but the essence of that adage is evident even in that country, with its constant earthquake consciousness. Memories return to an October evening in 1985, when Tokyo shuddered through what was then the biggest quake to hit it since 1923. Damage this time was fairly light, and injuries were few — testament to the solidness of Japanese engineering and to a popular resolve in the face of disaster.

And yet.

In the Ginza entertainment district, the audience in an 11th-floor movie theater was watching “Prizzi’s Honor” when the large hall started to bounce up and down and then sway from side to side. No one screamed, but you could hear a collective deep breath of fear. The audience raced out, and ran straight to the elevators. All those years of Sept. 1 exercises, and still they did the one thing they had been trained not to do.